* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 14px;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background-color: #fff;
    border-bottom: 1px solid #e0e0e0;
    padding: 15px 0;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 20px;
    font-weight: 600;
    color: #333;
    text-decoration: none;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 30px;
}

nav a {
    color: #666;
    text-decoration: none;
    transition: color 0.2s;
}

nav a:hover,
nav a.active {
    color: #333;
}

.main-content {
    padding: 40px 0;
}

.card {
    background-color: #fff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 20px;
    margin-bottom: 20px;
}

.card-header {
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid #f0f0f0;
}

.card-title {
    font-size: 18px;
    font-weight: 600;
    color: #333;
}

footer {
    background-color: #fff;
    border-top: 1px solid #e0e0e0;
    padding: 20px 0;
    margin-top: 40px;
}

.footer-content {
    text-align: center;
    color: #999;
    font-size: 12px;
}

.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.login-box {
    background-color: #fff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 40px;
    width: 100%;
    max-width: 400px;
}

.login-title {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 30px;
    text-align: center;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: #555;
}

input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
select,
textarea {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 3px;
    font-size: 14px;
    transition: border-color 0.2s;
}

input[type="text"]:focus,
input[type="password"]:focus,
input[type="email"]:focus,
input[type="number"]:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: #999;
}

textarea {
    resize: vertical;
    min-height: 100px;
}

.btn {
    display: inline-block;
    padding: 8px 16px;
    background-color: #333;
    color: #fff;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    font-size: 14px;
    text-decoration: none;
    transition: background-color 0.2s;
}

.btn:hover {
    background-color: #555;
}

.btn-block {
    display: block;
    width: 100%;
}

.btn-secondary {
    background-color: #666;
}

.btn-secondary:hover {
    background-color: #888;
}

.btn-danger {
    background-color: #dc3545;
}

.btn-danger:hover {
    background-color: #c82333;
}

.alert {
    padding: 12px 16px;
    border-radius: 3px;
    margin-bottom: 20px;
}

.alert-error {
    background-color: #fee;
    color: #c33;
    border: 1px solid #fcc;
}

.alert-success {
    background-color: #efe;
    color: #3c3;
    border: 1px solid #cfc;
}

.alert-info {
    background-color: #e9f5ff;
    color: #0066cc;
    border: 1px solid #cce5ff;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th {
    background-color: #f8f8f8;
    text-align: left;
    padding: 12px;
    font-weight: 600;
    color: #555;
    border-bottom: 2px solid #e0e0e0;
}

td {
    padding: 12px;
    border-bottom: 1px solid #f0f0f0;
}

tr:hover {
    background-color: #fafafa;
}

.text-muted {
    color: #999;
}

.text-right {
    text-align: right;
}

.mb-0 {
    margin-bottom: 0;
}

.mt-20 {
    margin-top: 20px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.stat-card {
    background-color: #fff;
    border: 1px solid #e0e0e0;
    border-radius: 4px;
    padding: 20px;
}

.stat-value {
    font-size: 32px;
    font-weight: 600;
    color: #333;
}

.stat-label {
    color: #999;
    font-size: 14px;
    margin-top: 5px;
}

.tabs {
    display: flex;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 20px;
}

.tab {
    padding: 10px 20px;
    color: #666;
    text-decoration: none;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
    transition: all 0.2s;
}

.tab:hover {
    color: #333;
}

.tab.active {
    color: #333;
    border-bottom-color: #333;
}

.settings-group {
    margin-bottom: 30px;
}

.settings-group h3 {
    font-size: 16px;
    margin-bottom: 15px;
    color: #333;
}